Yup. There are APIs to grab scores, achievements, user/friend info etc. So just ask GameKit for whatever data you want to display and draw it however you please. There are some limitations as too how much data you can pull at once so be sure to read the docs.

i have made a tableview to show players like leaderboard, however when i call [self loadView]; (code below) when i retrive top ten scores, loadview don't wait the end of loading request and the table results empty. the standard leaderboard has a UIActivityIndicatorView that not fills the table till finished. how can i implement a custom leaderboard?

I'm really not the guy to offer advice on UIKit, but I do know you don't want to call into UIKit from inside a block without first dispatching to the main queue/thread. And I'm almost certain you shouldn't be calling loadView.

Apple has a "GKTapper" example project that might help, or at least show what a convoluted mess you've gotten yourself into